Wet chemistry can be used to put small platinum particles on a ceramic surface in order to create a catalyst. However, when the catalyst is heated up and used, the platinum particles are not sufficiently bonded to the ceramic surface. As a result, they are mobile, allowing them to move around and find other platinum particles. Upon the platinum particles' discovery of each other, they agglomerate into bigger platinum particles.
For example, even if prior art processes start with ½ nanometer platinum particles, by the time the aging test has been performed (equivalent to 10 years on a car), the platinum particles have agglomerated to become 16 nanometer particles.
This agglomeration of platinum particles results in a massive reduction in catalytic surface area. As a result, the performance of the catalyst significantly decreases.